Angioplasty is a procedure used to enlarge pathological narrowing of the arteries which supply the heart muscle with blood. The usual procedure involves introducing a catheter containing a guide wire with a very flexible tip which advances ahead of the catheter and negotiates twists and turns without perforating or causing other damage to the wall of the artery. When the guide wire is observed to be through a narrowed portion of the artery, the catheter is slipped along the guide wire to a position at which a thin walled balloon fixed to the outside of the catheter is within the narrowed portion of the artery.
The thin walled balloon is connected to a source of physiological saline solution. Once the balloon is within the narrowed portion of the artery, the saline solution is pumped into the thin walled balloon, thereby causing the thin walled balloon to expand enough so as to widen the lumen of the artery sufficiently to establish the original blood flow.
Examples of balloon catheters can be found in U.S. Pat. Nos. 4,983,167 to Sahota; 4,777,951 to Cribier et al; 4,763,654 to Jang; 4,630,609 to Chin; and 4,456,000 to Schjeldahl et al.
If the narrow portion of the artery becomes so narrowed that either a guide wire or a balloon catheter cannot be inserted therein, balloon catheter systems will be unusable.
An alternative to balloon catheters is the use of toposcopic catheters or topocatheters. In the usual application of a topocatheter, the end of the catheter is turned inside or inverted forming a double walled tube which is continuous with itself so that the outer tube and the inner tube have their open ends facing the same direction. When the outer tube is connected to a source of pressurized liquid, the fluid flow first acts to close the open end of the inner tube and the fluid pressure which builds up after the end of the tube closes acts against the distal end of the device to make space by causing the inner tube to evert until the outer tube lengthens at the expense of the inner tube which results in a reformation of the original tube open at both ends.
In addition to dilation procedures which open narrowed blood vessels, and procedures involving topocatheters, other procedures have been developed to remove and extract emboli which block vascular passageways. For example, U.S. Pat. No. 3,996,938 to Clark, III discloses an expanding mesh catheter which can be manipulated from the configuration shown in FIG. 1 to that shown in FIG. 2 in order to contact and remove a clot from a vessel.
U.S. Pat. No. 3,635,223 to Klieman discloses an embolectomy catheter having an inflatable balloon 23 that has a plurality of rearward angled protrusions 27 which are used to engage and remove an embolus.
U.S. Pat. No. 2,701,559 to Cooper discloses an apparatus for exfoliating and collecting diagnostic material from the inner walls of hollow viscera which includes an inflatable balloon 22 having a tufts 25 or nodules 26 on the surface thereof.
The present invention provides a method and apparatus for entering and enlarging vessel constrictions which are too narrow for passing a conventional balloon catheter therethrough. In addition, the present invention provides a multifingered apparatus which can be used to recover target objects, including emboli from blood vessels.